Aetiology

Causes of breathlessness include:

Physiological dyspnoea: the normal breathlessness that accompanies exercise, the onset of which is dependent on the individual's fitness.

Cardiac disease:

• pulmonary venous congestion due to left heart failure of any cause

Lung disease:

• obstructive airways disease, e.g. acute asthma
• chronic airflow limitation, e.g. chronic bronchitis and/or emphysema
• parenchymal lung disease, e.g. fibrosing alveolitis, sarcoidosis, pneumoconiosis: initially produce dyspnoea on exertion. Crackles are usually present on auscultation.
• pulmonary vascular disease, e.g. pulmonary emboli, pulmonary hypertension
• chest wall abnormality, e.g. obesity, kyphoscoliosis
• respiratory muscle weakness, e.g. Guillain-Barre, syndrome, polio, myasthenia gravis
• pneumothorax
• pulmonary collapse

Other causes, e.g. psychogenic hyperventilation, altitude sickness, anaemia.

Breathlessness may also be considered in terms of acute causes and chronic causes

Reference

1. Hale ZE, Singhal A, Hsia RY. Causes of Shortness of Breath in the Acute Patient: A National Study. Acad Emerg Med. 2018 Nov;25(11):1227-34.